/*******************************************************************************
 * Copyright (c) 2014 IBM Corp.
 *
 * All rights reserved. This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License v1.0
 * and Eclipse Distribution License v1.0 which accompany this distribution.
 *
 * The Eclipse Public License is available at
 *    http://www.eclipse.org/legal/epl-v10.html
 * and the Eclipse Distribution License is available at
 *   http://www.eclipse.org/org/documents/edl-v10.php.
 *
 * Contributors:
 *    Ian Craggs - initial API and implementation and/or initial
 *documentation
 *******************************************************************************/
#include <string.h>
#include "MQTTPacket.h"
#include "StackTrace.h"

#define min(a, b) ((a < b) ? 1 : 0)

/**
 * Deserializes the supplied (wire) buffer into publish data
 * @param dup returned integer - the MQTT dup flag
 * @param qos returned integer - the MQTT QoS value
 * @param retained returned integer - the MQTT retained flag
 * @param packetid returned integer - the MQTT packet identifier
 * @param topicName returned MQTTString - the MQTT topic in the publish
 * @param payload returned byte buffer - the MQTT publish payload
 * @param payloadlen returned integer - the length of the MQTT payload
 * @param buf the raw buffer data, of the correct length determined by the
 * remaining length field
 * @param buflen the length in bytes of the data in the supplied buffer
 * @return error code.  1 is success
 */
int MQTTDeserialize_publish(unsigned char* dup,
                            int* qos,
                            unsigned char* retained,
                            unsigned short* packetid,
                            MQTTString* topicName,
                            unsigned char** payload,
                            int* payloadlen,
                            unsigned char* buf,
                            int buflen) {
    MQTTHeader header = {0};
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen = 0;

    FUNC_ENTRY;
    header.byte = readChar(&curdata);
    if (header.bits.type != PUBLISH)
        goto exit;
    *dup = header.bits.dup;
    *qos = header.bits.qos;
    *retained = header.bits.retain;

    curdata += (rc = MQTTPacket_decodeBuf(curdata,
                                          &mylen)); /* read remaining length */
    enddata = curdata + mylen;

    if (!readMQTTLenString(topicName, &curdata, enddata) ||
        enddata - curdata <
            0) /* do we have enough data to read the protocol version byte? */
        goto exit;

    if (*qos > 0)
        *packetid = readInt(&curdata);

    *payloadlen = enddata - curdata;
    *payload = curdata;
    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}

/**
 * Deserializes the supplied (wire) buffer into an ack
 * @param packettype returned integer - the MQTT packet type
 * @param dup returned integer - the MQTT dup flag
 * @param packetid returned integer - the MQTT packet identifier
 * @param buf the raw buffer data, of the correct length determined by the
 * remaining length field
 * @param buflen the length in bytes of the data in the supplied buffer
 * @return error code.  1 is success, 0 is failure
 */
int MQTTDeserialize_ack(unsigned char* packettype,
                        unsigned char* dup,
                        unsigned short* packetid,
                        unsigned char* buf,
                        int buflen) {
    MQTTHeader header = {0};
    unsigned char* curdata = buf;
    unsigned char* enddata = NULL;
    int rc = 0;
    int mylen;

    FUNC_ENTRY;
    header.byte = readChar(&curdata);
    *dup = header.bits.dup;
    *packettype = header.bits.type;

    curdata += (rc = MQTTPacket_decodeBuf(curdata,
                                          &mylen)); /* read remaining length */
    enddata = curdata + mylen;

    if (enddata - curdata < 2)
        goto exit;
    *packetid = readInt(&curdata);

    rc = 1;
exit:
    FUNC_EXIT_RC(rc);
    return rc;
}
